In the general art of manual instruments for performing orthopedic surgery, such as osteotomies, curets, gouges, chisels, and the like, the instruments have been fabricated of a single piece to form both a handle and the tool portion for performing the surgical operations. Each instrument was configured such that the tool portion was associated with the particular form of operation. Because these instruments have been integrally formed, when the tool portion becomes worn or broken through use, the entire instrument must be either reconditioned or discarded. If the damage occurs during an operation, a new instrument must be readily available to the surgeon so as to continue the operation. Of course, replacement and/or reconditioning of such instruments can be extremely costly.
Certain tools outside of the medical field, such as wrenches, have been devised which have tool portions which are detachable from the tool handle so as to permit the replacement of the tool portion when desired. Further, some of these tools are designed to permit interchangeable tool portions for tools are disclosed in U.S. Pat. Nos. 1,006,661, issued to M. A. Knapp on Oct. 24, 1911; 1,413,101, issued to S. J. Cushing on Apr. 18, 1922; 2,231,252, issued to W. L. Chesterman on Feb. 11, 1941; 2,832,246, issued to F. W. Livermont on Apr. 29, 1958; 2,832,943, issued to M. Cutler on Apr. 29, 1958; and 3,039,340, issued to F. W. Livermont on June 19, 1962.
The coupling means utilized by the devices of these patents, as used to releasably secure the tool portions to the handle portions, are not readily adaptable to use with surgical instruments. In this regard, most surgical instruments are relatively small in size, and the coupling means must be capable of being scaled accordingly while producing a strong and durable coupling. It is necessary, in the case of surgical instruments, that various forces be delivered to the handle portions, with these forces being fully delivered to the tool portions. This includes axial forces, as produced by a "hammer", and transverse forces created by movement of the handle portion by the surgeon. Further, the coupling mechanism that would be used with surgical instruments must permit very rapid changing of the tool portion: the couplings described in the above-cited patents will not meet these requirements.
Other tools and devices generally of interest are disclosed in the following U.S. Pat. Nos.: 4,473,070, issued to L. S. Matthews, et al. on Sept. 25, 1984; 4,601,289, issued to S. J. Chiarizzio, et al on July 22, 1986; 3,685,058, issued to R. G. Tronzo on Aug. 22, 1972; 2,312,B69, issued to C. A. Boyer on Mar. 2, 1943; Des. 272,648, issued to R. C. Bolesky, et al. on Feb. 14, 1984; 4,587,964, issued to C. B. Walker on May 13, 1986; and 4,124,026, issued to K. Berner, et al. on Nov. 7, 1978. See also German Pat. No. 2,906,068, issued on June 25, 1980 and the SYNTHES Product Catalog.
A departure from the one-piece surgical instrument was made with the instrument shown and described in the above-referenced U.S. Pat. No. 4,813,413 issued to the present inventor on Mar. 21, 1989. The teachings of this patent are incorporated herein by reference. The instrument of this patent provided for the rapid exchange of the tool portion for whatever reason: damage to the tool member; or the requirement for a tool member of a different configuration. This permitted a surgeon to retain a grip on the handle during this exchange such that there was little lost motion caused by the change. While most of the desired characteristics of a surgical instrument were present with the device of this patent, some movement (principally transverse) between the tool member and the handle member occurs even when very close tolerances are used in the making of the coupling components.
Therefore, it is an object of the present invention to provide a surgical instrument that has a readily detachable tool member.
A further object of the present invention is to provide a surgical instrument having a coupling member between a handle member and a detachable tool member that permits complete transfer of all transverse and axial forces from the handle member to the tool member.
It is also an object of the present invention to provide a surgical instrument having a readily detachable tool member that, in addition to transmitting all transverse and axial forces from the handle member to the tool member, further prevents rotational movement between the tool member and the handle.
Still another object of the present invention is to provide a surgical instrument having a readily detachable tool member that, in addition to transmitting all transverse and axial forces from the handle member to the tool member, further automatically orients the tool member to a desirable orientation with respect to the handle member.
These and other objects of the present invention will become apparent upon a consideration of the drawings that follow, together with the detailed description given thereafter.